Effect of agricultural microplastic and mesoplastic in the vermicomposting process: Response of Eisenia fetida and quality of the vermicomposts obtained.

This work evaluates the effect of agricultural plastic waste (APW) in two particle sizes, microplastic and film debris, and subjected to a pre-treatment by exposure to UV-C, in the development of the vermicomposting process. Eisenia fetida health status and metabolic response and the vermicompost quality and enzymatic activity were determined. The environmental significant of this study is mainly related to how can affect plastic presence (depending on plastic type, size and/or if it is partially degraded) not only to this biological process of organic waste degradation, but also to the vermicompost characteristics, since these organic materials will be reintroduced in the environment as organic amendments and/or fertilizers in agriculture. The plastic presence induced a significant negative effect in survival and body weight of E. fetida with an average decrease of 10% and 15%, respectively, and differences on the characteristics of the vermicomposts obtained, mainly related with NPK content. Although the plastic proportion tested (1.25% f. w.) did not induce acute toxicity in worms, effects of oxidative stress were found. Thus, the exposure of E. fetida to AWP with smaller size or pre-treated with UV seemed to induce a biochemical response, but the mechanism of oxidative stress response did not seem to be dependent on the size or shape of plastic fragments or pre-treated plastic.

Stable C and N isotope variation during anaerobic digestate composting and in the compost-amended soil-plant system.

Although the use of composts derived from anaerobic digestates as soil amendments is likely to increase in the future, there is little information concerning the fate of their C and N compounds after their incorporation into soil. This work assesses C and N concentrations and the associated changes in δ15N and δ13C during the composting processes of cattle and pig slurry anaerobic digestates. In addition, the compost effect on C and N fractions and plant uptake were studied during a six-month pot experiment with rosemary plants. The results did not show δ13C and δ15N isotopic discrimination during composting, indicating a previous stabilization of cattle manure and pig slurry during the anaerobic digestion. This fact was also confirmed by the low C losses during the composting processes (1.2-fold and 1.05-fold for the composting piles with cattle and pig slurry anaerobic digestates, respectively). After soil addition, the composts augmented N values (from 0.41 g kg-1 to around 0.56 g kg-1 in low dose and 0.68 g kg-1 in high dose compost amended soils) and δ15N soil values (increases in the range of 50%-156%), but showed only slight differences in C and δ13C values compared to unfertilised control and inorganic fertilized soils. Moreover, the rosemary leaves of the plants grown on the compost amended soils presented higher N and δ15N abundance than control and inorganic fertilized plants. We conclude that δ15N abundance of anaerobic digestate composts is useful to discern its N uptake and could thus be a useful tool to detect whether organic or mineral fertiliser types were used for agricultural production.

Role of proteins and soluble peptides as limiting components during the co-composting of agro-industrial wastes.

The agri-food industry is at the centre of the circular economy, since the co-composting of its residual flows allows their management and adds value producing fertilisers. In this work, six composting piles were prepared combining agri-food sludge (AS), different fresh vegetable wastes (pepper waste (P), tomato waste (T), and leek waste (L), and, as bulking agents, vine shoot pruning (VS), garlic stalks (GS) and avocado leaves (AL)). Classical physico-chemical and chemical determinations and advanced instrumental methods (excitation-emission fluorescence (EEM) and gravimetric (TG, DTG and DTA) techniques) were used and compared to assess organic matter evolution and evaluate the quality of the composts obtained. The thermal profiles of the composting processes were viable to show the stabilization of the agri-food sludge with the different materials tested in the mixtures, reaching adequate levels of stabilization of organic matter. Preferential degradation of peptides and proteins was observed by fluorescence. This seemed to induce a limitation in the biodegradation of the remaining organic matter, indicating that these biomolecules are key in composting dynamics, acting as limiting components during the process. The results from thermogravimetric analysis indicated the degradation of labile compounds (e.g., carbohydrates and proteins), the most recalcitrant material becoming predominant at the maturity stage of the composting process. The rise in the thermogravimetric parameter R2 was associated with the increase in the concentration of more refracting compounds, which need more energy for their decomposition.

Olive mill wastewater-evaporation ponds long term stored: Integrated assessment of in situ bioremediation strategies based on composting and vermicomposting.

During the last two decades, the method most widely used to manage olive mill wastewater (OMW) derived from olive oil production has been its disposal in evaporation ponds. Long-term storage of OMW leads to the accumulation of toxic sediments (OMWS) rich in recalcitrant compounds with phytotoxic and antimicrobial properties, which limit their use for agronomic purpose. The aim of this study was to compare the effect of two in situ bioremediation strategies (composting and a combination of composting followed by vermicomposting) to remove the potential toxicity of the sediments derived from long-term stored OMW. The results obtained showed that the composting method assisted with the earthworms enhanced the depletion of phenolic compounds and OMWS ecotoxicity more than composting, especially during the maturation stage. Moreover, vermicomposting was more effective in the reduction of the OMWS salinity. However, a pre-composting process to the OMWS is necessary prior to vermicomposting to provide the suitable conditions for earthworms survival and activity. Furthermore, the final compost showed a phytostimulating effect. Therefore, these in situ bioremediation strategies can be considered potential tools for decontamination and recovery of long-term stored OMWS in evaporation ponds, which currently poses an unsolved environmental problem.

Comprehensive management of dog faeces: Composting versus anaerobic digestion.

The objective of this work was to study the possibilities to manage and recycle dog faeces (DF) using biological processes, using two approaches: composting (C) and anaerobic digestion (AD). Thus, different experiments have been carried out: i) two laboratory/pilot scale experiments (self-heating and composting tests) and one, on a commercial scale; ii) two AD experiments. In both approaches, municipal waste such as the organic fraction of municipal solid waste (OMSW) and urban pruning waste (GW) were used as co-substrates. The results obtained regarding the optimization of the composting process indicated that the best strategy was the use of a 1:2 ratio of DF, a 1:4 ratio of OMSW, and a 1:4 ratio of GW, according to the thermal parameters studied (temperature and cumulative quadratic exothermic index (EXI2)), and the quality of the compost obtained. A potentially limiting factor of the process was the high salinity of the DF waste. In addition, AD experiments were performed on DF, OMSW, and GW wastes in controlled anaerobic systems at a laboratory scale. In these experiments, the biogas production obtained was 229 mL biogas/g total solids for the DF residue, 248 mL biogas/g total solids for GW, and 263 mL biogas/g total solids for OMSW. The co-digestion yields a clear improvement in the efficiency of the process against the use of a single residue, increasing the production of biogas by up to 27% with respect to that of the DF waste alone during the first 25 days of AD. The results obtained with these procedures have shown the possibilities to add value to this waste in an urban context where the circular economy represents an increasingly favourable scenario, including the generation of fertilisers and/or energy at a local scale, provided that the collection of dog faeces is optimized.

Reducing the composting time of broiler agro-industrial wastes: The effect of process monitoring parameters and agronomic quality.

The aim of this study was to evaluate the effect of considering different composting times on compost quality before the end of the bio-oxidative phase and after the maturation and storage phases. This study may provide useful information to optimize the composting process and increase the economic feasibility of the technology and its adoption without decreasing the quality of the end-product. In this study, three composts were prepared using chicken meat processing wastes mixed with urban tree trimmings, serving as a bulking agent, to evaluate the effect of reducing the durations of the bio-oxidative phase and the maturity stage on the different physico-chemical properties. Specifically, we evaluate water-soluble organic matter transformations by using excitation-emission matrix (EEM) fluorescence spectroscopy. The obtained results have shown that a composting time of 35 days combined with eight turnings was efficient for achieving the standard process control parameters for agro-industrial waste composting in the studied conditions and allowed for the production of stable and mature compost that is suitable for agricultural use.

The effect of anaerobic digestate derived composts on the metabolite composition and thermal behaviour of rosemary.

The study reports on the effect of anaerobic digestate derived composts on the metabolite composition and thermal behaviour of rosemary (Rosmarinus officinalis L.). Plants were cultivated in semiarid soil under four different fertiliser treatments (composts of anaerobic digested cattle (C) or pig slurry (P) at 30t/ha and 60 t/ha, and two control treatments (inorganic fertiliser and no fertiliser application). Samples of leaves and stems were analysed to investigate the effect of treatment on chemical composition and thermochemical properties. Three orthogonal analytical approaches were used, namely: Fourier transform mid infrared spectroscopy (FTIR), gas chromatography/mass spectrometry (GC/MS) and thermochemical gravimetric analysis (TGA). FTIR and GC/MS showed fertiliser treatment resulted in tissue specific changes in sample metabolite composition. Fertiliser treatment was detected to change the thermogravimetric properties of the leaf samples and from inorganic and composted pig slurry digestate treatments had greater ash content and lower proportions of fixed carbon compared with samples from the unfertilised control treatment. This study provides information on how the composition of rosemary might be altered by fertiliser application in regions of poor soil, and has implications for biomass quality when rosemary is grown on semi-wild sites for the purpose of soil improvement.

Gluten-free-rendered products contribute to imbalanced diets in children and adolescents with celiac disease.

PURPOSE: As well as adhering to the safe limit for gluten intake, a suitable gluten-free (GF) diet must also be nutritionally balanced. However, malnutrition has been observed in the population with celiac disease (CD). This is even more important in the case of children and adolescents, whose GF diet must also ensure their proper growth. The aim of the present study was to assess the diet quality of children and adolescents with CD to attain optimal nutritional status, determining the most relevant factors that affect a balanced diet. METHODS: Eighty-three children and adolescents with CD (9.2 ± 3.8 years) took part in the study. Height, weight and body composition were measured. An analysis of energy consumption and of the macronutrient distribution of their diet was carried out. Adherence to Mediterranean diet by KIDMED index was analyzed, and energy and nutrients intake. RESULTS: The diet of participants was not balanced, containing more fat and less carbohydrate than recommended. Most children and adolescents revealed adequate body mass index and suitable body fat percentage. Two-thirds of them showed moderate or poor KIDMED index, the case of girls being remarkable. When the GF diet, containing GF-rendered foodstuffs, was compared to a similar type of diet but substituting GF products with their analogs containing gluten, important nutritional differences were revealed. CONCLUSIONS: Even though celiac children and adolescents' diet is unhealthy due to its inappropriate dietary pattern, following a diet based on GF products raises extra difficulty in complying with the nutritional recommendations.

Valorization of date palm (Phoenix dactylifera L.) pruning biomass by co-composting with urban and agri-food sludge.

In the Mediterranean countries, there is an increasing production of date palm wastes (Phoenix dactylifera L.), not only due to the raising production of date palm fruits, but also derived from the maintenance of urban and peri-urban green areas, especially in those affected by red palm weevil (Rhynchophorus ferrugineus). The management of this increasing volume of green wastes usually concludes with a controlled disposal that implies an important loss of resources, in terms of organic matter, nutrients and energy. In addition, the rise of wastewater generation and the incentive of the wastewater treatment processes have derived in an increase of the amount of the sludge produced, which makes difficult its management. This work studies the feasibility of co-composting palm wastes with sludge from the urban and agri-food sectors as alternative treatment to manage these organic waste streams and to obtain added-value compost. For this, four mixtures (P1, P2, P3 and P4) were prepared using as main component palm leave waste (PL) mixed with different types of sludge. In the piles P1, P2 and P3, sewage sludge (SS) was used as co-composting agent, while agri-food sludge (AS) was used in P4. Throughout composting, the thermal profile of the composting piles was assessed, as were physical, chemical, physico-chemical and maturity parameters. In addition, the changes in water-soluble organic matter were assessed using chemical analytical methods and the excitation-emission matrix (EEM) fluorescence spectroscopy. The results obtained showed the viability of the co-composting process to obtain end-products with adequate maturity degree and physical characteristics for their potential use as substrates, except for the salt contents that can limit their use in some agricultural sectors.

Composting of the invasive species Arundo donax with sewage and agri-food sludge: Agronomic, economic and environmental aspects.

This work evaluates several co-composting scenarios based on the use of Arundo donax biomass (AD) as bulking agent for the co-composting of sewage sludge (MS) and agri-food sludge (AS), to manage these organic wastes and to produce balanced organic fertilizers by optimizing the process. For this, six piles were prepared in commercial composting conditions, using AD in a range of 40%-80% (on a dry weight basis). Physico-chemical and chemical parameters and the thermal behaviour were evaluated during the process, as were the physical and chemical parameters of the final composts. The proportion of AD in the mixtures has a significant effect on the development of the thermophilic stage of composting, showing the piles with higher proportion of AD a quicker organic matter degradation. In addition, the evolution of the thermal indices R1 and R2 was different depending on the origin of the sludge used, indicating an increase in the relative concentration of more recalcitrant materials in the piles prepared with AS. The estimation of the global warming potential showed that the use of higher proportion of AD in the composting mixture may be a strategy to mitigate the emission of greenhouse gases during the composting process. Moreover, the end-products obtained had an additional marketable value, with a balanced nutrient content and a good degree of maturity, which indicates the viability of the composting process as a method for the stabilization of these organic wastes.

Fatty acids, vitamins and cholesterol content, and sensory properties of cheese made with milk from sheep fed rapeseed oilcake.

The aim of the present study was to evaluate the influence of rapeseed oilcake used for feeding sheep on the content of fatty acids (FA), tocopherols, retinoids, and cholesterol of milk and cheese, and on the sensory properties of cheese. Indoor animal feeding (in winter) is the highest cost of production for cheesemakers, and the inclusion of locally produced rapeseed oilcake in the concentrate feed formulation can reduce the cost of cheese production, as long as the quality of the cheese is not altered. The experiment was carried out in March (mid lactation) with 72 Latxa sheep from an experimental farm located in the Basque Country (northern Spain). Two homogeneous groups of animals (n = 36) were set to receive each a different diet based on commercial or rapeseed concentrate, respectively, and forage (Festuca hay). Animal production parameters were individually recorded for each feeding group, whereas bulk milk from each group was used for cheesemaking trials. The rapeseed concentrate had higher amounts of unsaturated FA (mainly C18:1 cis isomers, C18:2 cis-9,cis-12 and C18:3 cis-9,cis-12,cis-15) and tocopherols than the commercial concentrate. The inclusion of rapeseed oilcake in the diet of dairy sheep did not compromise animal production parameters or milk gross composition. Bulk milk and cheese from sheep fed rapeseed concentrate showed higher content of unsaturated FA and tocopherols than those from sheep fed commercial concentrate. No differences were observed in the content of retinoid in milk and cheese between feeding groups, whereas the cholesterol content was slightly lower in cheese made with milk from sheep fed rapeseed concentrate. Thus, milk and cheese from sheep fed rapeseed concentrate had a healthier lipid profile. In addition, the inclusion of rapeseed oilcake in the diet of sheep did not change the typical sensory attributes of Protected Denomination of Origin Idiazabal cheese. Therefore, rapeseed concentrate could be a good local resource for feeding sheep to improve the nutritional quality of dairy products and to provide higher returns to farms.

Development of organic fertilizers from food market waste and urban gardening by composting in Ecuador.

Currently, the management of urban waste streams in developing countries is not optimized yet, and in many cases these wastes are disposed untreated in open dumps. This fact causes serious environmental and health problems due to the presence of contaminants and pathogens. Frequently, the use of specific low-cost strategies reduces the total amount of wastes. These strategies are mainly associated to the identification, separate collection and composting of specific organic waste streams, such as vegetable and fruit refuses from food markets and urban gardening activities. Concretely, in the Chimborazo Region (Ecuador), more than 80% of municipal solid waste is dumped into environment due to the lack of an efficient waste management strategy. Therefore, the aim of this study was to develop a demonstration project at field scale in this region to evaluate the feasibility of implanting the composting technology not only for the management of the organic waste fluxes from food market and gardening activities to be scaled-up in other developing regions, but also to obtain an end-product with a commercial value as organic fertilizer. Three co-composting mixtures were prepared using market wastes mixed with pruning of trees and ornamental palms as bulking agents. Two piles were created using different proportions of market waste and prunings of trees and ornamental palms: pile 1 (50:33:17) with a C/N ratio 25; pile 2: (60:30:10) with C/N ratio 24 and pile 3 (75:0:25) with C/N ratio 33), prepared with market waste and prunings of ornamental palm. Throughout the process, the temperature of the mixtures was monitored and organic matter evolution was determined using thermogravimetric and chemical techniques. Additionally, physico-chemical, chemical and agronomic parameters were determined to evaluate compost quality. The results obtained indicated that all the piles showed a suitable development of the composting process, with a significant organic matter decomposition, reached in a shorter period of time in pile 3. At the end of the process, all the composts showed absence of phytotoxicity and suitable agronomic properties for their use as organic fertilizers. This reflects the viability of the proposed alternative to be scaled-up in developing areas, not only to manage and recycle urban waste fluxes, but also to obtain organic fertilizers, including added value in economic terms related to nutrient contents.

Phosphorus availability from rock phosphate: Combined effect of green waste composting and sulfur addition.

Rock phosphate constitutes a natural phosphorus (P) source for organic farming systems, but with a limiting direct agricultural use due to its poor inherent reactivity. Thus, this work studies the effect of the co-composting of rock phosphate with green wastes and elemental sulfur on phosphorus availability. Six composts were prepared combining different green wastes and rock phosphate in three different proportions (0%, 0.27% and 0.54% P fresh mass basis) and elemental sulfur in two proportions (0% and 0.5% S fresh mass basis). During composting, the temperature of the mixtures was monitored, as were physico-chemical and chemical parameters, especially those related to phosphorus. The co-composting of green wastes with rock phosphate improved phosphorus mobilization and also constituted a viable method to manage green wastes, obtaining P-enriched compost for organic farming systems. Sulfur addition favored the composting process and also phosphorus solubilization, especially in the mixture with the lowest proportion of rock phosphate.

Thermal and spectroscopic analysis of organic matter degradation and humification during composting of pig slurry in different scenarios.

In this work, different analytical techniques (thermal analysis, (13)C cross-polarization magic angle spinning (CPMAS) NMR and Fourier transform infrared (FT-IR) spectroscopy) have been used to study the organic matter changes during the co-composting of pig slurry with cotton gin waste. To ensure the validity of the findings, the composting process was developed in different scenarios: under experimental pilot plant conditions, using the static pile system, and under real conditions on a pig farm, using the turning pile system. Also, the thermal stability index (R1) was determined before and after an extraction with water, to evaluate the effect of eliminating water-soluble inorganic salts on the thermal analysis. The results of the thermal methods showed the degradation of the most labile organic matter during composting; R1 increased during composting in all piles, without any influence of the presence of water-soluble inorganic ions in the sample. The NMR showed a decrease in the abundance of the carbohydrate molecules and an increase in the aliphatic materials during composting, due to a concentration effect. Also, FT-IR spectroscopy was a useful technique to study the trends of polysaccharides and nitrate, as indicators of organic matter transformations during composting.

Case study of a commercial sheep flock under extensive mountain grazing: Pasture derived lipid compounds in milk and cheese.

Terpenoid, fat-soluble antioxidant and fatty acid (FA) composition of pasture as well as those of milk and cheese from a commercial sheep flock managed under extensive mountain grazing in the east region of the Cantabrian mountain (Northern Spain) was investigated. The grazing period lasted for 2 months and ewes were at late lactation stage. Plants, feces, bulk milk and cheese samples were collected on two sampling dates. The abundance of the dominating botanical families in the mountain pasture prevailed in the sheep diet of the commercial flock. Major terpenoids and tocols in the pasture appeared as major ones in milk and cheese, whereas C18 unsaturated FAs in milk and cheese were derived from the intake of C18 polyunsaturated FAs which were prevalent in the pasture. No carotene was detected in the dairy samples but retinol (free or esterified), derived from the intake of ß-carotene present in pasture plants, was found in milk and cheese.

Chemical, Thermal and Spectroscopic Methods to Assess Biodegradation of Winery-Distillery Wastes during Composting.

The objective of this work was to study the co-composting process of wastes from the winery and distillery industry with animal manures, using the classical chemical methods traditionally used in composting studies together with advanced instrumental methods (thermal analysis, FT-IR and CPMAS 13C NMR techniques), to evaluate the development of the process and the quality of the end-products obtained. For this, three piles were elaborated by the turning composting system, using as raw materials winery-distillery wastes (grape marc and exhausted grape marc) and animal manures (cattle manure and poultry manure). The classical analytical methods showed a suitable development of the process in all the piles, but these techniques were ineffective to study the humification process during the composting of this type of materials. However, their combination with the advanced instrumental techniques clearly provided more information regarding the turnover of the organic matter pools during the composting process of these materials. Thermal analysis allowed to estimate the degradability of the remaining material and to assess qualitatively the rate of OM stabilization and recalcitrant C in the compost samples, based on the energy required to achieve the same mass losses. FT-IR spectra mainly showed variations between piles and time of sampling in the bands associated to complex organic compounds (mainly at 1420 and 1540 cm-1) and to nitrate and inorganic components (at 875 and 1384 cm-1, respectively), indicating composted material stability and maturity; while CPMAS 13C NMR provided semi-quantitatively partition of C compounds and structures during the process, being especially interesting their variation to evaluate the biotransformation of each C pool, especially in the comparison of recalcitrant C vs labile C pools, such as Alkyl /O-Alkyl ratio.

Drought and soil amendment effects on monoterpene emission in rosemary plants.

The aim of this work was to study the changes during 15days in the monoterpene emission rates of the Mediterranean shrub rosemary (Rosmarinus officinalis L.), in response to increasing drought stress and fertilisation using two different composts derived from livestock anaerobic digestates (cattle and pig slurry). Drought stress considerably reduced photosynthetic rates, stomatal conductance and isoprenoid emissions and also induced a change in blend composition. In the drought stressed rosemary plants, a positive relationship of non-oxygenated monoterpene emissions and a negative relationship of oxygenated monoterpene with photosynthesis were observed, indicating a different control mechanism over the emissions of the two types of isoprenoids. The emission of non-oxygenated monoterpenes seemed to depend more on photosynthesis and "de novo" synthesis, whereas emission of oxygenate monoterpenes was more dependent on volatilisation from storage, mainly driven by cumulative temperatures. In the short term, the addition of composted organic materials to the soil did not induce a significant effect on isoprenoid emission rates in the rosemary plants. However, the effect of the interaction between fertilisation and seasonality on isoprenoid emission rates was influenced by the amendment origin. Also, we emphasized changes in potential isoprenoid emission factors throughout the experiment, probably indicating changes in the leaf developmental stage.

Nutritional differences between a gluten-free diet and a diet containing equivalent products with gluten.

The gluten-free (GF) products market represents one of the most prosperous markets in the field of food and beverages in the immediate future. Historically, counselling for celiac disease has focused on the absence of gluten in foods, however the nutritional quality of GF foodstuffs is an important aspect to consider. The aim of the present work was to compare the nutritional composition of the 206 GF rendered products most consumed in Spain, against the composition of 289 equivalent foods with gluten, and to make a comparison between the diet including GF products and the same diet with equivalent products with gluten in a 58 adult celiac population. The results of the present collaborative study pointed out differences in calorie, macronutrient, fiber, sodium, salt and cholesterol content between GF rendered and gluten-containing foodstuffs. Thus, calorie and nutrient intake in a GF diet is different when compared to its equivalent diet with gluten. Following a diet based on GF products could suppose a nutritional imbalance for celiac patients as well as for non-celiacs who follow a diet that includes many GF rendered foodstuffs.